Childhood CT scans and cancer risk: impact of predisposing factors for cancer on the risk estimates

Journy, Neige; Roué, Tristan; Cardis, Elisabeth; Pointe, Hubert Ducou Le; Brisse, H.; Chateil, Jean‐François; Laurier, Dominique; Bernier, Marie‐Odile

doi:10.1088/0952-4746/36/1/n1

Cited by 47 publications

(51 citation statements)

References 14 publications

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“…We were able to incorporate data on cancer predisposing factors, which have been shown to be of importance recently. 28,30 Inclusion of cases with Down syndrome would have increased the risk estimates, possibly because Down syndrome is associated with increased risks of both leukemia and infections. 4,40 We also explored the joint effect of Down syndrome and cumulative RBM dose and found no interaction.…”

Section: Discussionmentioning

confidence: 99%

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Radiation exposure from computerized tomography and risk of childhood leukemia: Finnish register-based case-control study of childhood leukemia (FRECCLE)

Nikkilä

Raitanen²,

Lohi

et al. 2018

Haematologica

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The only well-established risk factors for childhood leukemia are high-dose ionizing radiation and Down syndrome. Computerized tomography is a common source of low-dose radiation. In this study, we examined the magnitude of the risk of childhood leukemia after pediatric computed tomography examinations. We evaluated the association of computed tomography scans with risk of childhood leukemia in a nationwide register-based case-control study. Cases (n=1,093) were identified from the population-based Finnish Cancer Registry and three controls, matched by gender and age, were randomly selected for each case from the Population Registry. Information was also obtained on birth weight, maternal smoking, parental socioeconomic status and background gamma radiation. Data on computed tomography scans were collected from the ten largest hospitals in Finland, covering approximately 87% of all pediatric computed tomography scans. Red bone marrow doses were estimated with NCICT dose calculation software. The data were analyzed using exact conditional logistic regression analysis. A total of 15 cases (1.4%) and ten controls (0.3%) had undergone one or more computed tomography scans, excluding a 2-year latency period. For one or more computed tomography scans, we observed an odds ratio of 2.82 (95% confidence interval: 1.05 – 7.56). Cumulative red bone marrow dose from computed tomography scans showed an excess odds ratio of 0.13 (95% confidence interval: 0.02 – 0.26) per mGy. Our results are consistent with the notion that even low doses of ionizing radiation observably increase the risk of childhood leukemia. However, the observed risk estimates are somewhat higher than those in earlier studies, probably due to random error, although unknown predisposing factors cannot be ruled out.

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Section: Discussionmentioning

confidence: 99%

“…underlying conditions predisposing children to both CT scans and leukemia. 28–30 Nevertheless, the evidence is still limited and the magnitude of the risk needs to be characterized further.…”

Section: Introductionmentioning

confidence: 99%

Radiation exposure from computerized tomography and risk of childhood leukemia: Finnish register-based case-control study of childhood leukemia (FRECCLE)

Nikkilä

Raitanen²,

Lohi

et al. 2018

Haematologica

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“…In all the previously reported epidemiological studies, the analyses were conducted after excluding cancers occurring within the first 1-10 years after exposures to reduce the possibility that scans were performed to investigate early symptoms of a tumour diagnosed later. [3][4][5][6][7] Ad hoc analyses 7,14,15 showed little to no evidence of an overestimation of radiation-related risks owing to the presence of cancer-predisposing conditions, such as Down syndrome, neurofibromatosis or ataxia telangiectasia, or immune deficiencies known to be associated with an elevated risk of haematopoietic tumours. 16,17 To complement these findings, we aim here to describe medical conditions associated with the use of CT in children or young adults with no previous diagnosis of cancer, among members of the previously reported UK CT cohort.…”

Section: Introductionmentioning

confidence: 99%

Medical conditions associated with the use of CT in children and young adults, Great Britain, 1995–2008

Journy¹,

McHugh²,

Harbron³

et al. 2016

The British Journal of Radiology

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Objective: To describe the medical conditions associated with the use of CT in children or young adults with no previous cancer diagnosis. Methods: Radiologist reports for scans performed in 1995-2008 in non-cancer patients less than 22 years of age were collected from the radiology information system in 44 hospitals of Great Britain. By semantic search, an automated procedure identified 185 medical conditions within the radiologist reports. Manual validation of a subsample by a paediatric radiologist showed a satisfactory performance of the automatic coding procedure. Results: Medical information was extracted for 37,807 scans; 19.5% scans were performed in children less than 5 years old; 52.0% scans were performed in 2000 or after. Trauma, diseases of the nervous (mainly hydrocephalus) or the circulatory system were each mentioned in 25-30% of scans. Hydrocephalus was mentioned in 19% of all scans, 59% of scans repeated $5 times in a year, and was the most frequent condition in children less than 5 years of age. Congenital diseases/malformations, disorders of the musculoskeletal system/connective tissues and infectious or respiratory diseases were each mentioned in 5-10% of scans. Suspicionor diagnosis of benign or malignant tumour was identified in 5% of scans. Conclusion: This study describes the medical conditions that likely underlie the use of CT in children in Great Britain. It shows that patients with hydrocephalus may receive high cumulative radiation exposures from CT in early life, i.e. at ages when they are most sensitive to radiation. Advances in knowledge: The majority of scans were unrelated to cancer suspicion. Repeated scans over time were mainly associated with the management of hydrocephalus. INTRODUCTIONThe benefits of CT, in the diagnosis and follow-up of numerous conditions, are undeniable. The justification for CT scanning must be balanced against the potential harmful effects of radiation exposures, particularly in children, who appear to be at a greater risk of radiation-related cancer than adults.1,2 Increased cancer risks in relation to CT exposures at young ages have been reported in several populations. The UK CT cohort study showed a significant dose-response relationship between radiation doses from scans received before the age of 22 years and the risk of cerebral tumours and leukaemia/myelodysplastic syndromes.3 After a first scan before the age of 10 years, 1 excess case of leukaemia and 1 excess case of cerebral tumour per 10,000 head scans were estimated to occur in the subsequent 10 years. Other cohort studies have found comparable results. 4-7The interpretation of these results nevertheless requires an understanding of whether the excess risks of later malignancies observed after CT scans were due to the radiation exposure or to the underlying medical condition. 8,9 It is indeed possible that the increased incidence rates observed after receipt of CT scans were, at least in part, attributable to the indication for CT use, whether it was the first symptoms of a tumour, a fol...

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“…RadRAT incorporates an extended list of cancer site-specific risk models that were previously derived by the US National Research Council in the BEIR VII report (NRC, 2006) from cohorts of survivors of the Hiroshima and Nagasaki atomic bombings and patients receiving radiotherapy for benign diseases or repeated diagnostic procedures. The above-mentioned recent studies on CT exposures cannot provide a full picture of radiation-related risks, mainly because their duration of follow-up is still too short to describe cancer incidence after the age of 50 years (Pearce et al , 2012; Mathews et al , 2013; Huang et al , 2014; Berrington de Gonzalez et al , 2016; Journy et al , 2016). In consequence, most of these studies estimated risks for a limited range of cancer sites.…”

Section: Methodsmentioning

confidence: 99%

“…Since then, direct evidence of increased cancer risks after CT scans received in childhood or early adulthood has been provided in epidemiological studies (Pearce et al , 2012; Mathews et al , 2013; Huang et al , 2014; Journy et al , 2016), although there were uncertainties in the dose estimates and a possibility of bias owing to underlying medical conditions (Walsh et al , 2014; Berrington de Gonzalez et al , 2016). These studies have enhanced awareness about potential risks of X-ray exposures among the medical community and, along with considerable technological progress in CT, has led to further radiation dose optimisation in paediatrics.…”

mentioning

confidence: 99%

Projected cancer risks potentially related to past, current, and future practices in paediatric CT in the United Kingdom, 1990–2020

et al. 2016

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Background:To project risks of developing cancer and the number of cases potentially induced by past, current, and future computed tomography (CT) scans performed in the United Kingdom in individuals aged <20 years.Methods:Organ doses were estimated from surveys of individual scan parameters and CT protocols used in the United Kingdom. Frequencies of scans were estimated from the NHS Diagnostic Imaging Dataset. Excess lifetime risks (ELRs) of radiation-related cancer were calculated as cumulative lifetime risks, accounting for survival probabilities, using the RadRAT risk assessment tool.Results:In 2000–2008, ELRs ranged from 0.3 to 1 per 1000 head scans and 1 to 5 per 1000 non-head scans. ELRs per scan were reduced by 50–70% in 2000–2008 compared with 1990–1995, subsequent to dose reduction over time. The 130 750 scans performed in 2015 in the United Kingdom were projected to induce 64 (90% uncertainty interval (UI): 38–113) future cancers. Current practices would lead to about 300 (90% UI: 230–680) future cancers induced by scans performed in 2016–2020.Conclusions:Absolute excess risks from single exposures would be low compared with background risks, but even small increases in annual CT rates over the next years would substantially increase the number of potential subsequent cancers.

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Childhood CT scans and cancer risk: impact of predisposing factors for cancer on the risk estimates

Cited by 47 publications

References 14 publications

Radiation exposure from computerized tomography and risk of childhood leukemia: Finnish register-based case-control study of childhood leukemia (FRECCLE)

Radiation exposure from computerized tomography and risk of childhood leukemia: Finnish register-based case-control study of childhood leukemia (FRECCLE)

Medical conditions associated with the use of CT in children and young adults, Great Britain, 1995–2008

Projected cancer risks potentially related to past, current, and future practices in paediatric CT in the United Kingdom, 1990–2020

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